It's a pretty simple process, although a little more involved than a whole blood donation. The initial screening process is the same as for a regular blood donation. After that you go settle into one of their nice comfy chairs and get ready to relax for about 90 minutes. During that time you can relax, nap or watch a movie. Don't bother bringing a book because you won't be able to read it. Today, there were 3 pheresis machines, but only two had TVs set up. Guess which one I got. Fortunately my brain is pretty good at entertaining itself.
Next to you is the machine that takes your blood, spins out the platelets and plasma and returns the rest to you. It's big with lots of tubing and a little on the noisy side but not too bad. It's like being next to a car.
Plasma/platelet apheresis is a two needle process with one removing blood from one arm and the other returning red cells/saline to the other arm. Since you can't move your arms, it's pretty hard to read anything.
For me the process took just under 90 minutes. Aside from getting stuck by two needles, there wasn't really any discomfort at all. I ended up spending most of the time napping, so the donation felt like it went pretty quickly. The staff checks up on you periodically to make sure everything is going smoothly. I thought it was pretty cool watching the machine work and seeing the plasma bag fill up.
Once the machine goes through the equivalent of your entire blood volume (about 5 liters), you're all done, one needle comes out and then you just have to wait a couple more minutes for the machine to finish putting the red cells back in. The second needle comes out and you have two bandage wrapped arms. The bag containing the platelets comes out of the pheresis machine partly filled with yellowish clumpy looking stuff. Some of the plasma is used to dilute the platelets and they're transferred into another bag. Then off you go to have a drink and some snacks and make sure you're not feeling any ill effects from the donation.
If you're looking for a good excuse to get away for a couple hours and have to sit and do nothing, think about doing a plasma and/or platelet donation!